US2928514A - Overrunning spring clutch - Google Patents

Description

March 15, 1960 c. l. CLAUSING ETAL 2,928,514

OVERRUNNING SPRING CLUTCH Filed April 29, 1957 Ill IN VEN TOILS CH/M & Afr I Clams/Ml United States Patent F OVERRUNNING SPRING CLUTCH Application April 29, 1957, Serial No. 655,688

3 Claims. (Cl. 192-41) Our invention relates to a clutch for engaging a driving and a driven member for rotation of the driving member in a first direction and disengaging the driving and driven members responsive to rotation of the driving member in an opposite direction wherein a spring having concentric windings is utilized.

As may be seen in copending application Serial No. 537,444, filed September 29, 1955, entitled Disengageable Spring Clutch to Challiss I. Clausing and Anthony P. Romano and assigned to the assignee of the instant application, now Patent No. 2,883,022, granted April 21, 1959, spring clutch devices for connecting and disconnecting a driving and driven member responsive to a rotation of the driving member in a first or second direction have been provided which utilize a wound helical spring. One end of the helical spring is fastened to the driving member whilethe other end of the spring fits in a diameter of the driven member. By rotating the driver in a direction which is the same as the direction of the spring winding, the spring would tend to tighten or decrease its inner diameter to thereby grip the driven member to couple the driving and driven members if the spring is on an outer diameter of the driven member. When, however, the driving member is rotated in an opposite direction and opposite to the direction of the spring winding, the spring diameter will increase whereby the coupling between the spring and the driven member slips and the driving and driven members are uncoupled.

In all applications of the helical spring clutch device, it has been found that the relationship between the spring diameter and the diameter of the member which is to be coupled to the spring during clutching operations must be at relatively critical values with respect to one another to achieve the desired clutching operation, since the clutch characteristics are radically altered when the spring diameter varies by a relatively small amount.

Another disadvantage of the above noted type of spring device is that the clutch must have an axial length which is at least equal to the axial length of the helical spring utilized. Thus the compactness of the clutch is limited by this value.

The principle of the instant invention is to utilize a spring coupling member which is in the form of a concentrically wound spring wherein each turn lies within the adjacent turn as in the commonly used clock main spring. a

Thus one end of the spring is fastened to the driving or 2,928,514- Patented Mar. '15, 1960 By way of example, this novel spring clutch could be so constructed that the spring is positioned internally of an annular shaped area of the driving member with its outer turn attached thereto. The driven member may then be positioned within the internal diameter of the spring whereby rotation of the driving member in a first direction will cause the inner turn of the spring to frictionally engage the driving member in a direction to wind the spring whereby a rigid engagement is obtained between the two members. When, however, the driving member is rotated in an opposite direction, the spring will be unwound and the driving and driven members will be unclutched.

If desired, the spring could be of the so-called negator type wherein the spring will always tend to have the same diameter when in the unstressed condition. Thus the spring could normally engage the driven member when in its natural state and this engagement will be defeated only when the driving member is driven in a direction which will unwind the spring.

In either of the above cases, the dimensions of the shaft receiving the spring is not critical, and the clutch is of relatively. small size.

Accordingly, a primary object of our invention is to provide a novel spring clutch for coupling a driving and driven member for rotation of the driving member in a first direction and uncoupling the driving and driven member for rotation of the driving member in a second direction.

Another object of our invention is to provide a novel spring clutch device utilizing a concentrically wound spring member.

A still further object of our invention is to provide a novel spring clutch device having a relatively short axial length.

Still .another object of our invention is to provide a novel spring clutch wherein large tolerances for the diameters of the driving or driven members are permissible without affecting the clutch characteristics.

A still further object of our invention is to provide a novel overrunning spring clutch which utilizes the negator type spring for the clutching element.

These and other objects of our invention will become apparent from the following description when taken in connection with the drawings, in which:

Figure 1 is a side partial crosssectional view of our novel spring clutch when the driving member and driven members are coupled together.

Figure 2 is a cross-sectional view of Figure 1 when taken across the lines 2-2.

- Figure 3 is similar to Figure 1 where the driving and driven members are uncoupled from one another.

Figure 4 is a side cross-sectional view of an unwound negator type spring which could be utilized as the clutching member in the embodiment of Figures 1, 2 and 3.

Referring now to Figures 1 and 2, the driving member is seen as comprising the cup-shaped member 10 having a fiat cover plate 12 connected thereto by fastening screws 14 and 16. The bottom of cup-shaped member 10 has a circular opening therein as does the center of cover 12 for accepting the shaft 18 which could be the driven member.

The shaft 18 has bushing 20 rigidly connected thereto in any desired manner so that the bushing 20is positioned within the cup-shaped opening of member 10. Thus in assembling the device of Figures 1 and 2, it is clear that the'cup-shaped member 10 is fitted over the shaft 18 and bushing 20 is inserted in the opening of cup-shaped member 10. The cover piece 12 is thereafter fastened into position to restrict axial movement of shaft 18 as well as to provide a dust-free enclosure.

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